scholarly journals Ionospheric effects of two solar flares in the maximum of solar cycle 23 and in the minimum of solar cycle 24

2019 ◽  
Vol 5 (2) ◽  
pp. 76-80
Author(s):  
Владимир Смирнов ◽  
Vladimir Smirnov ◽  
Елена Смирнова ◽  
Elena Smirnova
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Total Duration ◽  
Rate Of Change ◽  
Satellite Systems ◽  
Solar Cycle 23 ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Using Data ◽  
Total Electronic Content

Using data from the GPS and GLONASS navigation satellite systems, we analyze the responses of the mid-latitude ionosphere to the extreme solar flares that occurred at the maximum of solar cycle 23 (October 28, 2003) and at the minimum of solar cycle 24 (September 6, 2017) during the same season at close solar zenith angles. To obtain the response, we use the rate of change of the total electronic content, which is practically independent of characteristics of equipment and is determined only by parameters of a propagation medium (the ionosphere in our case). The ionospheric response is shown to be almost independent of the total duration of the flare. In both cases, the duration of the main response at a level of 0.5 is about 1.5–2 min, whereas the total duration of the response is about 10 min and fairly independent of solar flare importance.

scholarly journals Ionospheric effects of two solar flares in the maximum of solar cycle 23 and in the minimum of solar cycle 24

2019 ◽  
Vol 5 (2) ◽  
pp. 82-88
Author(s):  
Владимир Смирнов ◽  
Vladimir Smirnov ◽  
Елена Смирнова ◽  
Elena Smirnova
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Total Duration ◽  
Rate Of Change ◽  
Satellite Systems ◽  
Solar Cycle 23 ◽  
Solar Cycle 24 ◽  
Cycle 24 ◽  
Using Data ◽  
Total Electronic Content

Using data from the GPS and GLONASS navigation satellite systems, we analyze the responses of the mid-latitude ionosphere to the extreme solar flares that occurred at the maximum of solar cycle 23 (October 28, 2003) and at the minimum of solar cycle 24 (September 6, 2017) during the same season at close solar zenith angles. To obtain the response, we use the rate of change of the total electronic content, which is practically independent of characteristics of equipment and is determined only by parameters of a propagation medium (the ionosphere in our case). The ionospheric response is shown to be almost independent of the total duration of the flare. In both cases, the duration of the main response at a level of 0.5 is about 1.5–2 min, whereas the total duration of the response is about 10 min and fairly independent of solar flare importance.

Solar flares, CMEs and solar energetic particle events during solar cycle 24

2018 ◽  
Vol 61 (2) ◽  
pp. 777-785 ◽  
Author(s):  
Bimal Pande ◽  
Seema Pande ◽  
Ramesh Chandra ◽  
Mahesh Chandra Mathpal
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Solar Energetic Particle Events ◽  
Solar Cycle 24 ◽  
Cycle 24

scholarly journals Descriptive study of X-class flares released in the year 2014, during the double peak of SC-24

2015 ◽  
Vol 11 (S320) ◽  
pp. 330-332
Author(s):  
Ahmed A. Hady ◽  
Marwa H. Mostafa ◽  
Susan W. Samwel
Keyword(s):  
Data Analysis ◽  
Solar Cycle ◽  
Solar Flares ◽  
Descriptive Study ◽  
Energetic Particles ◽  
Main Peak ◽  
Solar Cycles ◽  
Double Peak ◽  
Solar Cycle 24 ◽  
Cycle 24

AbstractDuring the declining phase of the Solar cycle 24, a new peak appeared on January 7, 2014. The release of x-class flares, with the high energetic particles, were found to be more intense than that occurred during the main peak of the same cycle. Few X-class flares were released, lately, during the year 2014. We note that during the last 5 solar cycles, a new peak has appeared, releasing high energetic particles and X-class solar flares, which are called the secondary peak or the double peak of solar cycle. The aim of this descriptive study is to follow the morphological and magnetic changes of the active region before, during, and after the production of X-class flares according to data analysis. Furthermore, the causes of the release of such eruptive storms have been discussed for the period, year 2014, during the double peak of the solar cycle 24.

A physics-based method that can predict imminent large solar flares

Science ◽  
2020 ◽  
Vol 369 (6503) ◽  
pp. 587-591 ◽  
Author(s):  
Kanya Kusano ◽  
Tomoya Iju ◽  
Yumi Bamba ◽  
Satoshi Inoue
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Solar Surface ◽  
Magnetic Polarity ◽  
Empirical Methods ◽  
Polarity Inversion ◽  
Solar Cycle 24 ◽  
Polarity Inversion Line ◽  
Magnetohydrodynamic Instability ◽  
Cycle 24

Solar flares are highly energetic events in the Sun’s corona that affect Earth’s space weather. The mechanism that drives the onset of solar flares is unknown, hampering efforts to forecast them, which mostly rely on empirical methods. We present the κ-scheme, a physics-based model to predict large solar flares through a critical condition of magnetohydrodynamic instability, triggered by magnetic reconnection. Analysis of the largest (X-class) flares from 2008 to 2019 (during solar cycle 24) shows that the κ-scheme predicts most imminent large solar flares, with a small number of exceptions for confined flares. We conclude that magnetic twist flux density, close to a magnetic polarity inversion line on the solar surface, determines when and where solar flares may occur and how large they can be.

Characteristics of Sunquake Events Observed in Solar Cycle 24

2021 ◽  
Author(s):  
Alexander Kosovichev ◽  
Ivan Sharykin
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Active Regions ◽  
Impulsive Phase ◽  
High Energy ◽  
Lower Atmosphere ◽  
Solar Dynamics Observatory ◽  
X Ray ◽  
Solar Cycle 24 ◽  
Cycle 24

<p>Helioseismic response to solar flares ("sunquakes") occurs due to localized force or/and momentum impacts observed during the flare impulsive phase in the lower atmosphere. Such impacts may be caused by precipitation of high-energy particles, downward shocks, or magnetic Lorentz force. Understanding the mechanism of sunquakes is a key problem of the flare energy release and transport. Our statistical analysis of M-X class flares observed by the Solar Dynamics Observatory during Solar Cycle 24 has shown that contrary to expectations, many relatively weak M-class flares produced strong sunquakes, while for some powerful X-class flares, helioseismic waves were not observed or were weak. The analysis also revealed that there were active regions characterized by the most efficient generation of sunquakes during the solar cycle. We found that the sunquake power correlates with maximal values of the X-ray flux derivative better than with the X-ray class. The sunquake data challenge the current theories of solar flares.</p>

scholarly journals The Statistical Analysis of Characteristics of Coronal Mass Ejection During the Descending Phase of Solar Cycle 23 and 24

2021 ◽  
Vol 16 (2) ◽  
Author(s):  
Hemlata Dharmashaktu ◽  
N.K. Lohani
Keyword(s):  
Solar Cycle ◽  
Angular Width ◽  
Maximum Speed ◽  
Solar Cycles ◽  
Linear Speed ◽  
23Rd Solar Cycle ◽  
23Rd Cycle ◽  
Solar Cycle 23 ◽  
Solar Cycle 24 ◽  
Cycle 24

The characteristics of CMEs we studied are angular width, linear speed, and acceleration for all categories of CMEs such as narrow (W ≤20°), intermediate (20°< W<200°), wide (W ≥ 200°) and linear speed <500 km/s during the descending phase of solar cycle 23 and 24 and compared them. We have found that there are 1951 narrow CMEs during solar cycle 23 that is 1.9 times greater than in solar cycle 24 (1047). On the other side, the number of intermediate CMEs during solar cycle 24 (1571) is 1.14 times more than solar cycle 23 (1162). We observed no noticeable difference between the number of wide CMEs of solar cycle 23 (29) and 24 (36). The angular width of CMEs during the descending phase of solar cycle 23 and solar cycle 24, predominately distributed around 100-600. The fascinating result is that the angular width distributions for the descending phase of solar cycles are approximately identical. On comparing the results of linear speed of both solar cycle, we can say that, (i) 93.7% (1729) and 87.7% (908) of narrow CMEs, (ii) 97% (1328) and 94% (1479) of intermediate CMEs and (iii) 44% (13) and 42% (15) of wide CMEs have speed of <500 km s-1, respectively. Mostly the fractions of narrow and intermediate CMEs decline sharply at the speeds greater than 500 km s-1. The maximum speed observed during the 23rd cycle is 1994 km/s (wide CME) and the 24th cycle is 3163 km/s (wide CME) respectively. It was noticed that the speed of the 24th solar cycle CME is higher than the 23rd solar cycle CME. The major fraction of CMEs has acceleration in the range of -20 to 20 km s-2, all types of CMEs. The narrow and intermediate CMEs mostly show acceleration while wide CMEs show deceleration.

Sign in / Sign up

Export Citation Format

Share Document